When Duthie was planting seeds in his garden, he "didn't even think about legionnaires' disease".

"[It's] something I've heard of but it was one of those things I never thought would affect me," Duthie said.

Even though he was gardening about two weeks ago, he only started to "feel rotten" last Tuesday.

"I never get sick and I've never been to hospital before and I just didn't know what was wrong with me."

Duthie visited his GP who told him to go to Christchurch Hospital. He said his sister, a nurse, suggested he could have legionnaires' disease, so he told hospital staff he had been in the garden.

"Having 40-degree temperatures and coughing non-stop is not fun . . . in future I'll definitely be wearing a mask, making sure bags of potting mix or whatever are kept damp and being careful when I open it."

He said too many people did "the typically Kiwi thing".

"They ignore the warnings, grab the pocket knife and rip into the bag . . . I'll be telling everyone I know to be more careful."

He said while a week-long hospital stay cost thousands of dollars, a simple protective mask cost "next to nothing".

Last year there were 61 cases recorded in Canterbury and three deaths.